Apparatus for producing sublimed lead.



L. s. HUGHES. APPARATUS FOR PRODUGING SUBLIMED LEAD. APPLICATION FILED JAN.13,1913.

1,070,688, I I x v Pdtented Aug.19,1 913.

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Fri t, ca h t IL LOVES Si HUGHES, 0E" CHICAG-Q, IL

Specification of To all whom it may concern Be it known lZl1Ll3"I,,LOUIS S.- Huenns, a'

citizen of the United States, residing at Chicago, in the county of Cool; and State of Illinois, have invented certain new and: useful Improvements in Apparatus for Producing Sublimed Lead of which the following is a specification, reference being bad therein to the accompanying drawing;

My invention relates to a new and improved apparatus for producing sublimed lead, and consists in the matters hereinafter described and then pointed out in the appended claims.

The manufacture of'sublimed lead is accomplished commercially by feeding lead bearing materials (largely native lead sul-- fid or a-lena) into an open coke'fire in short blast furnaces (the-soecalled low cupola furnaces), the fire being maintained by air blas s through tWyers near the bottom of the furnaces andcontinuous operation being secured by feeding with the coke and lead and sulfur bearing charge proper amounts of lime and iron to form a fluid slag with the silicious coke ash and gangue of the ore. Slagpots are provided for the removal of this slag. Th'ewhite fume of oxidized'lead compounds rises from the fire as a dense .wl-iite smoke and is-draWn from the furnace intoa horizontal 'brick flue wherethe last traces of ca'Ib0I 1 '(-soot) and lead sulfid are burned, and the gases and fume pass thence into a series of settling and cooling chambers .within which the last traces of tire dirts and iron oxid settle out, and after being thus purified by gravital' subsidence of the impurities and cooled by radiation until'the fume and gases can be passed through cloth filters they enter a screen system of the ordinary bag room-type where the air and furnace gases pass through the filter cloths and the fume is retained therein- "Draft for the furnaces and for drawing the gases and fume. through the flue and cooling system into-thebag {room is secured by placing a let e suction fan between thecooling system and the bag room This draws the gases and fume from the fu-rnaeeathrough the system iand forces-them; into the' filter system, the

fan, of course, actingas asuction fan'on one eideands pressu e-fan n the her.

Serial No. 'FGLGSS,

Letters Patent.

' The apparatus heretofore employed for the manufacture of sublimed lead comprises two 'or more low cupola furnaces placed side by side in tandem and opening intoa common combustion chamber which delivers into a brick flue placed at one end of the row of furnaces.

chamber at a level with the tops of the furnaces. At the end of the flue is a'serics of settling chambers and cooling pipes with suction flue to supply draft to the furnace doors and to convey the fumiforni pigmentto a screen system Whereiuit is collected iVhile the tire in the furnaces is maintained by blast twyers placed near'the bottom of the furnaces, very little, if any, of the air supplied by these tu'yers is aiailable for oxidation of the ore as it is deprived of its oxygen while passing over the incandescent coke Within the furnace and practically all of the furnaces. its the suction draws the air to one side as soon as it enters the feed doors and its expansion by heating upon toward the top ofthe combustion chamber whence it. is drawn into the fiuewithout again coming in contact- With the furnace top, the air is only" in effective contact with the chargenear the front edge of the furnace tops aiidthe rear of the furnace remains under a blanket of dead or reducing gas arising from the furnaces beloum- So exftrenie is this reducing condition the back cape through a hole in theback of the com bastion. chamber is black from unburned carbon and lead sulfid,

As "the oxidation by the furnaces is incomplete a Very considerable recovered with the slag, but this is an undesired and unprofitable by-product. Efforts have been made to secure more complete oxidation by the furnaces in order to reduce this proportion of pig lea-cl. Forenample the-use of single furnaces has been attempted but Without practical success as a air drawn into the feed doors over the tops entering the doorv tends to cause it to rise of the furnaces that smoke allowed to es-- singlefurnace cannot be employed comni'ercially for the reason that either through .-oe-' Feed doors are placed 1 along one side of the Wall of the combustion the oxidation of the ore .is, accomplished by proportion of the lead in the charge is reduced to inctaland is more furnaces abreast casional bad practice or irregular charging or obstruction in operation oi the furnace the fire becomes smoky instead of bright and thus fails to maintain the flue at e temperature sufiicient to consume all the discoloring smoke entering it. The result is the entry of discoloring carbon or vaporized sulfid into the collecting chamber with the conse quent discolcration of all the product then iii-the collecting chamber. As the velue of the product is dependent upon its whiteness and even a. trace of discoloration is suiiicient to render it velueless commercially, it is apparent that even the lapse of a few minutes in proper operation will ruin a whole days product Another arrangement consisted in placing furnaces at the ends of converging fiues but this failed because it is practically impossible to maintain an equal draft throu gh' the branches of a converging flue. If one furnace is (as must often be the case) hotter than the other the exgiiansion of air within it causes the draft to book entry through the cooler furnace and fine tosucli extent that hot furnace will emit smoke a not only :2.-

Y? t v poisonvapors in subliznui'e do mount of oxidatliu't-tliis yield ed if the entire "nae-c iteined under oxid of ind fierent or reducing conditio my present invention 1 maintain the flue at proper working heat andsecure complete oxidising conditions over the ent accomplish: ticw se results will v of the dining or L by placing two or i'ZlSU-BtlCl of tandem and by placing a draft port or ports at or near the top of the furnaces opposite the fad doors and enlarging the flue at its near end into a chamber whereby an equal draft is secured over the entire top of each furnace thus rendering effective for oxidation the entire area of the furnace top.

In the acc mpanying rawings which illustrate a practical emb of m p invention, Figure 1 is longitudinal horizontel sectional view showing the arrangement oithe furnaces, chamber and flue, and Fig. 2is a, longitudinal vertical sectional View of the same parts.

In the drawings the reference letter A designates-a -plurality of furnaces having feed doors'B and arranged in the inclosing housing or casing C abreast of each other with respect to the flue, and the casing provides a chamber D formed by an enlargement of the flue E and communicating with the area above the tops of the furnaces by ."a. draft port F formed by'the masonry of the casing with a fiat elied top. The

top the furnace and l j enses tice I have found that uniformity of dire-ft is secured by using a chamber six feet high, twelve feet Wide and twelve feet long provided with port of total cross-sectional ares not exceeding sixteen square feet arranged across its front end with a flue of cross-sectional area of approximately sixteen square feet, though of course these relative dimensions may be varied The chamber at its rear merges into the fiue which should be at least equal in cross-sectional area to the total area of the interior draft ports F of the furnace. The chamber is preferably circolor or elliptical. in its ground plan or horizontal cross-section as such formation eliminates the settling which otherwise occurs in corners and also furnishes a construction less liable to crack on heating.

As many furnaces as desired may l "1 arranged side by side, and in practice I prefer to make the draft port common to all fun naces employed as the less divisions there in it the less likely is it to fill up.

By the organization disclosed the effective with the charge over she e area of the furnace tops and c mpiete dizing; conditions are obtained thereby male ins, a larger yield of pigment and less lend. Also for this reason the queli f the pigment is betterend more uniform than by former apparatus. The enlargement of the flue constituting the chamber into which the draft ports lead diil'uscs or equalizes the suction influence of the Tine over the several furnaces so that an equal draft is efiected at all the furnace ports. The improved drafting of the furnaces maintains the flue at proper working heat so that the life of the apparatus is prolonged as there is no liability of its filling up by deposits which usually begin at the start of firing operations and accumulate during operation, and as the improveddrafting practically aerates the entire furnace chamber there are no wall accretions to cause shutdowns and impair the usefulness or interrupt theuse of the apparatus.

I claim v 1. In a device for producing sublimcd lead,' a plurality of furnaces arranged abreast and having air intakes near their tops, a flue, and a chamber between the flue and furnaces communicating with the latter by draft port near their tops said port having approximately the area of the cross-sectional area of the flue, and the chamber be ing larger-in diameter than the flue.

2. In a device forproducing sublimed lead, a plurality of furnaces arranged 'abreas: and having air and feed doors near their tops a flue, and a chamber between the flue I endfurnaces and communicating with the la-tter b y draft port opposite the feed doors, said port having approximately the area of thecross-sectiona]. area of the flue,

5 chamber being elliptical in ground plan and having its' sides merging into the sides of Copies of this patent may be obtained for five cents each, by addressing the commissioner of Patents,

7 Washington, D. G.

1,o7o,eee 5;

In testimohy whereof I affixmy sigTmt-ul'e in presence of two Witnesses.

and the LOUIS S. HUGHES.

Witnesses:

J. MGROBERTS,

H. C. LUST. 

